JP6882974B2 - Liquid blow molding method - Google Patents

Description

The present invention relates to a liquid blow molding method for molding a synthetic resin preform having a mouth portion into a container containing a liquid having a predetermined shape.

Synthetic resin containers such as polypropylene (PP) bottles and polyethylene terephthalate (PET) bottles contain various liquids such as beverages, cosmetics, chemicals, detergents, and toiletries such as shampoo. It is used for containment purposes. Such a container is generally manufactured by blow molding, for example, a preform formed in a bottomed tubular shape with a synthetic resin material having thermoplasticity as described above.

Further, as blow molding for molding a preform into a container, liquid blow molding is known in which a pressurized liquid is used instead of pressurized air as a pressure medium to be supplied to the inside of the preform.

For example, in Patent Document 1, a preform made of synthetic resin which has been preheated to a temperature at which stretchability is exhibited is set in a mold for blow molding, and a blow nozzle is passed through the inside of the preform to a predetermined pressure. Described is a liquid blow molding method in which the preform is molded into a container having a predetermined shape along a cavity of a mold by supplying a liquid pressurized to the above. According to such a liquid blow molding method, by using the content liquid to be finally contained in the container as a product such as a beverage as the liquid to be supplied to the preform, the container is molded and the content liquid to the container is charged. Filling can be performed at the same time to easily form (manufacture) a container containing a liquid containing the content liquid, whereby the step of filling the inside of the container after molding with the content liquid can be omitted, and the production thereof can be performed. The configuration of the process and production line (equipment) can be simplified.

On the other hand, as a filling device for filling the container with the content liquid, the air mixed in the liquid is separated from the liquid and removed by irradiating the liquid with ultrasonic waves in the path of sending the liquid toward the container. Then, it is known that the liquid is filled in a container (see, for example, Patent Document 2).

Japanese Patent No. 5806929 Japanese Unexamined Patent Publication No. 2004-041846

In the liquid blow molding method described in Patent Document 1, if air is contained in the liquid supplied to the preform as a pressure medium, foaming or the like occurs in the liquid in the preform, and the molding conditions are stabilized. There was a risk of causing problems such as deterioration of properties and moldability of the container.

On the other hand, it is conceivable to use a filling device as described in Patent Document 2 to remove air from the liquid supplied to the preform in advance, and then perform liquid blow molding.

However, in the filling device described in Patent Document 2, there is a concern that air may be mixed in the path after removing the air, and in the liquid blow molding method, the liquid supplied to the preform as a pressure medium is Since the air existing inside the preform is entrained and supplied to the inside of the preform, the liquid from which the air has been removed in advance is supplied to the preform by using a filling device as described in Patent Document 2 above. Even so, the foaming of the liquid cannot be sufficiently suppressed.

Further, when a suckback step of sucking back a predetermined amount of liquid from the container after molding is performed after liquid blow molding, the air entrained in the liquid in the liquid blow molding is returned to the liquid path by the suckback. However, it is difficult to remove air from the sucked-back liquid with a filling device as described in Patent Document 2.

The present invention has been made in view of such a problem, and an object of the present invention is to produce a liquid-containing container accurately and at low cost so as to have a predetermined content and shape. The purpose is to provide a molding method.

The liquid blow molding method of the present invention is a liquid blow molding method for molding a synthetic resin preform having a mouth portion into a container containing a liquid having a predetermined shape, from the mouth portion to the inside of the preform through a blow nozzle. A gas-liquid replacement step of supplying a liquid and discharging the air inside the preform to the outside, a gas-liquid separation step of vibrating the preform to separate air from the liquid inside the preform, and the qi. After the liquid separation step, it is characterized by having a blow molding step of supplying a pressurized liquid from the mouth portion to the inside of the preform through the blow nozzle and molding the preform into a container having a predetermined shape. To do.

In the liquid blow molding method of the present invention, it is preferable to perform the gas-liquid separation step while performing the gas-liquid replacement step in the above configuration.

In the liquid blow molding method of the present invention, in the above configuration, it is preferable to perform the gas-liquid separation step after the completion of the gas-liquid replacement step.

In the liquid blow molding method of the present invention, in the above configuration, it is preferable that the preform or the mold to which the preform is mounted is subjected to ultrasonic waves to vibrate the preform in the gas-liquid separation step.

In the liquid blow molding method of the present invention, in the above configuration, it is preferable that the preform is vibrated by bringing the vibrating body into contact with the preform or the mold on which the preform is mounted in the gas-liquid separation step.

In the above configuration, the liquid blow molding method of the present invention includes a nozzle engaging step of engaging the blow nozzle with the mouth portion before the gas-liquid replacement step, and in the gas-liquid replacement step, the blow While supplying liquid from the mouth to the inside of the preform through the liquid supply port of the nozzle, the air inside the preform is discharged to the outside from a discharge port provided in the blow nozzle separately from the liquid supply port. It is preferable to let it.

In the above configuration, the liquid blow molding method of the present invention includes a first nozzle lowering step of lowering the blow nozzle to a first position where the mouth portion is not sealed before the gas-liquid replacement step. In the liquid replacement step, while supplying the liquid from the mouth to the inside of the preform through the blow nozzle at the first position, the air inside the preform is blown from the gap between the blow nozzle and the mouth. It has a second nozzle lowering step of discharging the blow nozzle to the outside and lowering the blow nozzle to a second position where the mouth portion is sealed after the gas-liquid replacement step, and the blow molding after the second nozzle lowering step. It is preferable to carry out the process.

In the above configuration, the liquid blow molding method of the present invention preferably includes a suckback step of sucking back a predetermined amount of liquid from the inside of the container after molding through the blow nozzle after the blow molding step.

According to the present invention, it is possible to provide a liquid blow molding method capable of manufacturing a container containing a liquid accurately and at low cost so as to have a predetermined content and shape.

It is explanatory drawing which shows an example of the liquid blow molding apparatus used in the liquid blow molding method which is one Embodiment of this invention. It is an enlarged view which shows the main part of the liquid blow molding apparatus shown in FIG. 1 in an enlarged manner. It is explanatory drawing which shows the liquid blow molding apparatus in the state which preform is set in the mold. It is explanatory drawing which shows the liquid blow molding apparatus in the state which performs the gas-liquid separation process while performing the gas-liquid replacement process. It is explanatory drawing which shows the liquid blow molding apparatus in the state which the gas-liquid replacement process is completed. It is explanatory drawing which shows the liquid blow molding apparatus in the state which performs the blow molding process. It is explanatory drawing which shows the liquid blow molding apparatus in the state which performs the suckback process. It is explanatory drawing which shows the liquid blow molding apparatus in the state which the blow nozzle is separated from the mouth part of the container after molding.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

The liquid blow molding method of the present invention is a liquid blow molding method in which a preform made of synthetic resin having a mouth portion is molded into a container containing a liquid having a predetermined shape, and a liquid is blown from the mouth portion into the inside of the preform through a blow nozzle. After the gas-liquid replacement step of discharging the air inside the preform to the outside while supplying it, the gas-liquid separation step of vibrating the preform to separate the air from the liquid inside the preform, and the gas-liquid separation step. It is characterized by having a blow molding step of supplying a pressurized liquid from a mouth portion to the inside of the preform through a blow nozzle to form the preform into a container having a predetermined shape. Such a liquid blow molding method of the present invention can be said to be a method for manufacturing a liquid-containing container for manufacturing a liquid-containing container containing a content liquid from a preform.

The liquid blow molding method of the present invention can be carried out using, for example, the liquid blow molding apparatus 1 having the configuration shown in FIG.

The liquid blow molding apparatus 1 shown in FIG. 1 is a device in which a synthetic resin preform 2 is liquid blow molded and molded into a liquid-containing container containing a content liquid inside. Here, the liquid blow molding is a blow molding performed by using a pressurized liquid instead of the pressurized air used in the air blow molding as the pressure medium (pressurized fluid) supplied to the preform 2. Is.

As the liquid L supplied to the preform 2, that is, the content liquid L contained in the container containing the liquid after molding, various liquids such as beverages, cosmetics, chemicals, detergents, toiletries such as shampoo, etc. can be used. ..

As the preform 2, for example, a synthetic resin material having thermoplasticity such as polypropylene (PP) or polyethylene terephthalate (PET) connects the cylindrical mouth portion 2a as the opening end and the mouth portion 2a and closes the lower end. It is preferable to use one formed in a bottomed tubular shape having a cylindrical body portion 2b.

The preform 2 is not limited to the above shape, and any shape can be used as long as it has a mouth portion 2a, depending on the shape of the container after molding and the like.

Although details are not shown, on the outer wall surface of the mouth portion 2a of the preform 2, a closing cap (not shown) is attached to the mouth portion 2a of the molded liquid container by a stopper (undercut engagement). Engagement protrusions are provided. In addition, a male screw may be provided on the outer wall surface of the mouth portion 2a instead of the engaging protrusion, and the closing cap may be attached to the mouth portion 2a by screw connection.

The liquid blow molding apparatus 1 has a mold 10 for blow molding. The mold 10 has a cavity 11 having a shape corresponding to the final shape of the container, such as a bottle shape. The cavity 11 opens upward on the upper surface of the mold 10. The preform 2 is mounted on the mold 10 with the body portion 2b arranged inside the cavity 11 of the mold 10 and the mouth portion 2a protruding upward from the mold 10.

Although details are not shown, the mold 10 can be opened to the left and right, and the liquid-containing container is taken out from the mold 10 by opening the mold 10 to the left and right after molding the preform 2 into a liquid-containing container. be able to.

Above the mold 10, a nozzle unit 20 for supplying the liquid L to the inside of the preform 2 is provided. The nozzle unit 20 has a main body block 21, and the main body block 21 is movable relative to the mold 10 in the vertical direction. A support block 22 is provided at the lower end of the main body block 21, and a blow nozzle 23 is attached to the lower end of the main body block 21 supported by the support block 22. The blow nozzle 23 is formed in a substantially cylindrical shape, and is a preform attached to the mold 10 when the nozzle unit 20 moves relative to the mold 10 to the stroke end in a direction approaching the mold 10. Engage with the mouth portion 2a of 2 from above in a sealed state.

As shown in FIG. 2, the inner portion of the cylindrical portion of the blow nozzle 23 is the liquid supply port 23a. Further, the cylindrical portion forming the liquid supply port 23a of the blow nozzle 23 is provided with a discharge port 23b that opens at the lower end of the cylindrical portion. In the present embodiment, eight discharge ports 23b are provided in the cylindrical portion of the blow nozzle 23 at equal intervals in the circumferential direction, but the number thereof can be changed in various ways.

As shown in FIG. 1, a supply path 24 extending in the vertical direction is provided inside the main body block 21. The supply path 24 is a flow path for supplying the liquid L to the liquid supply port 23a of the blow nozzle 23, and communicates with the liquid supply port 23a of the blow nozzle 23 at the lower end thereof.

Further, the main body block 21 is provided with a supply port 25 communicating with the upper end of the supply path 24.

Inside the supply path 24, a seal body 26 for opening and closing the liquid supply port 23a of the blow nozzle 23 is arranged. The seal body 26 is fixed to the lower end of a shaft body 27 provided so as to be movable in the vertical direction with respect to the nozzle unit 20, and is movable in the vertical direction inside the supply path 24. The seal body 26 is formed in a columnar shape, and when it moves to the closed position which is the stroke end position on the lower side, it contacts the upper surface of the blow nozzle 23 on the lower end surface and closes the liquid supply port 23a of the blow nozzle 23. To do. On the other hand, when the seal body 26 moves upward from the closed position, the liquid supply port 23a of the blow nozzle 23 is opened and communicates with the supply path 24. The seal body 26 may be formed integrally with the shaft body 27.

As shown in the figure, the liquid blow molding apparatus 1 may be configured to include a drawing rod 28. The extension rod 28 is inserted into the axial center of the shaft body 27 so as to be relatively movable in the vertical direction with respect to the shaft body 27, and can penetrate the axial center of the seal body 26 and appear and disappear from the lower end of the seal body 26. It is provided. The extension rod 28 is driven by a drive source (not shown) and moves downward, so that the preform 2 can be extended in the axial direction. In the case where the stretching rod 28 is provided in this way, the liquid blow molding apparatus 1 uses the stretching rod 28 to stretch the preform 2 in the axial direction and supplies the pressurized liquid L from the mouth portion 2a. Biaxial stretch blow molding that stretches in the radial direction can be performed.

The liquid blow molding apparatus 1 may not be provided with the stretching rod 28, and may be configured to perform liquid blow molding only with the liquid L in which the preform 2 is pressurized.

A pump 30 is connected to the supply port 25 by a pipe P1. The pump 30 can be configured as a plunger pump including, for example, a cylinder 30a and a piston (plunger) 30b.

A supply tank 31 is connected to the pump 30. The supply tank 31 may be configured to accommodate the liquid L and to heat the liquid L to a predetermined temperature and hold the liquid L at the temperature. An on-off valve V1 is provided in the flow path between the pump 30 and the supply tank 31, and the on-off valve V1 can open and close the flow path. Reference numeral 32 is a pressure gauge provided on the pipe P1.

As shown in FIG. 2, the plurality of discharge ports 23b provided in the blow nozzle 23 are connected to a connecting path 23c provided in an annular shape on the outer peripheral surface of the blow nozzle 23 by a flow path that extends upward and bends outward in the radial direction. It is communicated. The connecting path 23c is connected to the connecting port 22a on the side surface of the support block 22. As shown in FIG. 1, a pipe P2 is connected to the connection port 22a, and the connection port 22a is connected to a discharge tank (not shown) via the pipe P2. That is, the plurality of discharge ports 23b provided in the blow nozzle 23 are each connected to the discharge tank. The pipe P2 can be connected to a suction pump for discharge instead of the discharge tank. The pipe P2 is provided with an on-off valve V2 that opens and closes the pipe P2.

The pump 30 pressurized to a predetermined pressure by operating in the forward direction (pressurizing direction) in a state where the seal body 26 moves upward, the liquid supply port 23a is opened, and the on-off valve V1 is closed. The liquid L can be supplied to the inside of the preform 2 through the pipe P1, the supply port 25, the supply path 24, and the liquid supply port 23a of the blow nozzle 23. Further, the pump 30 operates in the opposite direction in a state where the liquid supply port 23a is closed by the seal body 26 and the on-off valve V1 is opened, so that the liquid L contained in the supply tank 31 is transferred to the inside of the cylinder 30a. Can be sucked into and prepared for the next liquid blow molding.

The liquid blow molding apparatus 1 is provided with a vibration generator 40 for vibrating the preform 2. In the case shown in the figure, the vibration generator 40 is configured as an ultrasonic generator that generates ultrasonic waves, and is built in the mold 10. The vibration generator 40 generates ultrasonic waves (sound waves having a frequency of 20 kHz or more) inside the cavity 11 through the inner surface of the cavity 11 of the mold 10, and by applying the ultrasonic waves, the preform 2 is micronized at high speed. Can be vibrated.

In the case shown in the figure, the vibration generator 40 is built in the mold 10, but the present invention is not limited to this, and if the preform 2 can be vibrated, the arrangement location thereof can be changed in various ways. For example, the vibration generator 40 may be arranged outside the mold 10 and ultrasonic waves may be applied to the mold 10 in a non-contact manner to vibrate the preform 2 together with the mold 10 at high speed. Further, the vibration generator 40 may be arranged between the mold 10 and the nozzle unit 20 and ultrasonic waves may be applied to the mouth portion 2a of the preform 2 in a non-contact manner to cause the preform 2 to vibrate slightly at high speed. Further, the vibration generator 40 may be provided in the nozzle unit 20 and ultrasonic waves may be applied to the mouth portion 2a of the preform 2 from the side of the nozzle unit 20 in a non-contact manner to cause the preform 2 to vibrate slightly at high speed. Further, when the vibration generator 40 is provided in the nozzle unit 20, ultrasonic waves may be applied to the nozzle unit 20 in a non-contact manner to cause the preform 2 to vibrate at high speed together with the nozzle unit 20.

The vibration generator 40 is not limited to one that generates ultrasonic waves, and for example, a vibration generator 40 that generates a sound wave having a frequency of less than 20 kHz and vibrates the preform 2 by applying the sound wave may be adopted. it can.

Further, in the case shown in the drawing, the vibration generator 40 is configured as an ultrasonic generator, and ultrasonic waves are applied to the preform 2 in a non-contact manner to vibrate the preform 2, but the present invention is not limited to this. The vibration generator 40 may be in contact with the preform 2 (for example, the mouth portion 2a) and ultrasonic waves may be applied to vibrate the preform 2. Further, the mold 10 is vibrated by applying ultrasonic waves in a state where the vibration generator 40 provided on the outside of the mold 10 is in contact with the mold 10, and the vibration of the mold 10 is applied to the mouth of the preform 2. It may be configured to transmit to 2a and vibrate the preform 2 together with the mold 10. Further, the vibration generator 40 may be configured to vibrate the preform 2 together with the member by applying ultrasonic waves in a state where the vibration generator 40 is in contact with a member (for example, a blow nozzle 23) constituting the nozzle unit 20.

The operations of the nozzle unit 20, the seal body 26, the extension rod 28, the pump 30, the on-off valves V1, V2, the vibration generator 40, and the like are integrally controlled by a control device (not shown). This control can be performed with reference to the value of the pressure gauge 32 and the like. The on-off valves V1 and V2 are preferably composed of solenoid valves that can be controlled by a control device.

Next, using the liquid blow molding apparatus 1 having such a configuration, a liquid-containing container C in which the liquid (content liquid) L is contained inside a container having a predetermined shape is molded from the synthetic resin preform 2. A method (a liquid blow molding method according to the present embodiment) will be described.

First, as shown in FIG. 3, in a state where the nozzle unit 20 is separated upward from the blow molding die 10, the degree to which stretchability is exhibited by using a heating means (not shown) such as a heater in advance. The synthetic resin preform 2 which has been heated to a predetermined temperature (for example, 80 ° C. to 150 ° C.) is attached to the mold 10 and molded. When the mold clamping is completed, the preform 2 is in a state in which the mouth portion 2a protrudes upward from the upper surface of the mold 10 and the body portion 2b is arranged inside the cavity 11.

When the preform 2 is mounted on the mold 10, a nozzle engagement step is then performed. In the nozzle engagement step, the nozzle unit 20 is relatively moved in a direction approaching the mold 10, and the blow nozzle 23 is engaged with the mouth portion 2a of the preform 2 so as to be in a liquid-tight state. 1 and 2 show a completed state of the nozzle engagement step in which the blow nozzle 23 engages with the mouth portion 2a of the preform 2 in a liquid-tight state. In the completed state of the nozzle engagement step, the seal body 26 and the on-off valve V1 are closed, and the on-off valve V2 is open. Further, the stretching rod 28 is held in an in-situ position so as not to protrude downward from the blow nozzle 23.

When the nozzle engagement step is completed, the gas-liquid replacement step is then performed. In the gas-liquid replacement step, as shown in FIG. 4, the seal body 26 is moved upward to open the liquid supply port 23a of the blow nozzle 23 while the on-off valve V2, that is, the discharge port 23b is open. In this state, the pump 30 is operated in the forward direction (pressurizing direction). When the pump 30 operates, the liquid L is supplied to the inside of the preform 2 through the pipe P1, the supply port 25, the supply path 24, and the liquid supply port 23a of the blow nozzle 23.

Here, in the gas-liquid replacement step, the liquid L is supplied to the inside of the preform 2 in a state where the discharge port 23b provided in the blow nozzle 23 is opened and communicated with the discharge tank. As the liquid L is supplied to the inside, the air inside the preform 2 is pushed out from the discharge port 23b toward the discharge tank and discharged, and the inside of the preform 2 is replaced with the liquid L from the air. That is, by performing the gas-liquid replacement step, the air inside the preform 2 is replaced with the liquid L, and as shown in FIG. 5, the inside of the preform 2 remains in the shape before blow molding. It can be filled with liquid L.

In the gas-liquid replacement step, it is preferable to supply a predetermined amount of liquid L to the inside of the preform 2 at a lower pressure than in the blow molding step described later. That is, in the gas-liquid replacement step, it is preferable to adjust and operate the output of the pump 30 so that the liquid L is supplied at a pressure such that the preform 2 is not liquid blow molded or is slightly liquid blow molded. ..

In the liquid blow molding method of the present invention, in order to reduce the amount of air remaining inside the preform 2 after the completion of the gas-liquid replacement step, a gas-liquid separation step is performed before the preform 2 is blow molded. I am trying to do it. In the gas-liquid separation step, the vibration generator 40 is operated to vibrate the preform 2 to separate air from the liquid L inside the preform 2. In particular, in the present embodiment, by operating the vibration generator 40 and applying ultrasonic waves to the preform 2, the preform 2 is slightly vibrated at high speed, and air is separated from the liquid L inside the preform 2. .. By separating the air from the liquid L inside the preform 2, the air mixed in the liquid L is moved to the side of the mouth 2a of the preform 2 and is external from the discharge port 23b provided in the blow nozzle 23. Can be efficiently discharged.

In the present embodiment, the gas-liquid separation step is performed while performing the gas-liquid replacement step. That is, in the present embodiment, as shown in FIGS. 4 and 5, a gas-liquid replacement step is performed in a state where the preform 2 is vibrated by the vibration generator 40, and the inside of the vibrating preform 2 is inside. The liquid L is supplied through the liquid supply port 23a of the blow nozzle 23. The liquid L supplied to the inside of the preform 2 is separated from the air by the vibration of the preform 2 and collects on the bottom side of the preform 2. On the other hand, the air mixed in the liquid L is separated from the liquid L by the vibration, moves above the preform 2, and is discharged from the discharge port 23b provided in the blow nozzle 23 separately from the liquid supply port 23a. .. In this way, by supplying the liquid L to the inside of the preform 2 while vibrating the preform 2, the air mixed in the liquid L is separated from the liquid L and efficiently discharged to the outside from the discharge port 23b. The inside of the preform 2 can be filled with the liquid L while allowing the preform 2. Therefore, the amount of air remaining inside the preform 2 after the completion of the gas-liquid replacement step can be reduced.

In particular, when the liquid L is a liquid having a relatively high viscosity such as shampoo or liquid detergent, the liquid L containing air is supplied to the inside of the preform 2, or is supplied to the inside of the preform 2. In some cases, the liquid L entrains the air inside the preform 2 and contains a large amount of air. Even in such a case, the liquid L is mixed with the liquid L by performing the gas-liquid separation step. The existing air can be separated from the liquid L and efficiently discharged to the outside from the discharge port 23b.

In the liquid blow molding method of the present invention, the gas-liquid separation step may be performed after the completion of the gas-liquid replacement step without being performed during the gas-liquid replacement step. Even in this case, the air mixed in the liquid L by vibrating the preform 2 in the gas-liquid separation step with the preform 2 whose inside is filled with the liquid L by the gas-liquid replacement step. Can be separated from the liquid L and discharged to the outside from the discharge port 23b. Therefore, the amount of air remaining inside the preform 2 after the completion of the gas-liquid replacement step can be reduced.

The gas-liquid separation step can be continuously performed during both the gas-liquid replacement step and after the completion of the gas-liquid replacement step.

As described above, in the liquid blow molding method of the present embodiment, the air mixed in the liquid L inside the preform 2 is separated from the liquid L by vibrating the preform 2 in the gas-liquid separation step. Since it can be efficiently discharged to the outside from the discharge port 23b, the amount of air remaining inside the preform 2 after the completion of the gas-liquid replacement step can be reduced.

When the gas-liquid replacement step and the gas-liquid separation step are completed, a blow molding step is then performed. In the blow molding step, as shown in FIG. 6, the pump 30 is further operated in the forward direction while the on-off valves V1 and V2 are closed and the liquid supply port 23a is opened by the seal body 26. At this time, the pump 30 operates at an output such that the pressure of the liquid L supplied to the preform 2 becomes a predetermined pressure at which the preform 2 can be liquid blow molded. In this way, by supplying the liquid L further pressurized to a predetermined pressure inside the preform 2 filled with the liquid L, the preform 2 is stretched in an expanded manner by the pressure of the liquid L. Then, as shown in FIG. 6, when the preform 2 is molded (liquid blow molding) until it becomes a liquid-containing container C having a predetermined shape along the inner surface of the cavity 11, the operation of the pump 30 is stopped and blow molding is performed. The process is complete.

Here, as described above, the air inside the preform 2 is replaced with the liquid L in the gas-liquid replacement step, and the amount of air remaining inside the preform 2 is further increased by performing the gas-liquid separation step. Since the amount is reduced, it is possible to prevent air from being entrained in the liquid L supplied to the inside of the preform 2 in the blow molding process and causing foaming or the like to occur in the liquid L inside the preform 2, and the molding conditions. Can be stabilized and the moldability of the container can be improved. Therefore, the liquid-containing container C can be manufactured accurately and at low cost so as to have a predetermined content and shape.

When the stretching rod 28 is provided in the liquid blow molding apparatus 1, the stretching rod 28 is advanced and moved toward the inside of the preform 2 in the blow molding step, and the preform 2 is moved axially (longitudinal direction) by the stretching rod 28. Stretch to. As a result, biaxial stretching blow molding in which the preform 2 is stretched in the biaxial direction by the pressure of the liquid L and the stretching rod 28 can be performed. According to the biaxial stretching blow molding, the preform 2 can be molded into the liquid-containing container C having a predetermined shape with higher accuracy.

In the present embodiment, the suckback step is performed after the blow molding step is completed.

As shown in FIG. 7, in the suckback step, the pump 30 is operated in the opposite direction with the seal body 26 in the open position and the liquid supply port 23a of the blow nozzle 23 is open, and the shape is determined in the blow molding step. A predetermined amount of liquid L is sucked back (sucked back) into the supply path 24 from the inside of the liquid container C formed in the above through the liquid supply port 23a. The amount of the liquid L sucked back into the supply path 24 in the suckback step is appropriately set so that the head space HS provided inside the liquid container C after completion is a predetermined amount. When the suckback step is performed, the content of the liquid-containing container C is reduced by the amount of the liquid L sucked back into the supply path 24, and the container C is in a volume-reduced deformation state in which a gap is formed between the liquid-filled container C and the cavity 11. The inside is in a negative pressure state lower than the atmospheric pressure.

At this time, the air inside the preform 2 is replaced with the liquid L in the gas-liquid replacement step, and the amount of air remaining inside the preform 2 is further reduced by performing the gas-liquid separation step. Therefore, even if the liquid L is pulled back from the liquid container C to the inside of the supply path 24 by the sackback, a large amount of air does not mix in the liquid L inside the supply path 24, and the liquid to be performed next is performed. The moldability does not deteriorate in the blow molding process.

When the suckback step is completed, next, the blow nozzle 23 is provided by the seal body 26 with the predetermined amount of liquid L sucked back into the supply path 24 from the inside of the liquid-containing container C formed into a predetermined shape in the suckback step. After closing the liquid supply port 23a of the above, as shown in FIG. 8, the nozzle unit 20 is relatively moved in the direction away from the mold 10, the blow nozzle 23 is separated from the mouth 2a of the preform 2, and the blow nozzle 23 is used. Disengage from the mouth 2a. When the blow nozzle 23 is separated from the mouth portion 2a of the liquid-filled container C after molding, the liquid-filled container C, which had been in a volume-reduced deformation state in the suckback process, is restored to its original shape and is inside the liquid-filled container C. Is formed with a predetermined amount of headspace HS on top of a predetermined amount of liquid L. Before the blow nozzle 23 is disengaged, the on-off valve V2 is opened to communicate with the outside air, and the liquid-containing container C, which has been in a volume-reduced deformation state in the suckback process, is restored to its original shape to restore the head space. HS may be formed.

Then, in that state, a cap is attached to the mouth portion 2a by a closing device (not shown), and then the mold 10 is opened and the completed liquid-containing container C is taken out from the mold 10. The cap may be attached after the liquid container C is taken out from the mold 10.

When the draw rod 28 is provided in the liquid blow molding apparatus 1, the draw rod 28 may be pulled out from the liquid container C after the liquid supply port 23 a of the blow nozzle 23 is closed by the seal body 26. As a result, the amount of headspace HS can be further increased by the volume integral of the stretching rod 28 as compared with the case where the stretching rod 28 is not provided in the liquid blow molding apparatus 1. In this case, the amount of the liquid L sucked back from the inside of the liquid container C into the supply path 24 in the suckback step may be set in consideration of the volume of the drawing rod 28 inserted into the liquid container C.

As described above, in the liquid blow molding method of the present embodiment, the air inside the preform 2 is replaced with the liquid L in the gas-liquid replacement step, and the inside of the preform 2 is performed by performing the gas-liquid separation step. Since the amount of air remaining in the preform 2 is further reduced, air is entrained in the liquid L supplied to the inside of the preform 2 in the blow molding process, and foaming or the like occurs in the liquid L inside the preform 2. This can be suppressed, and the liquid-containing container C can be manufactured accurately and at low cost so as to have a predetermined content and shape.

At this time, in the gas-liquid replacement step, a predetermined amount of liquid L is supplied to the inside of the preform 2 at a pressure lower than that in the liquid blow molding step, so that the preform does not cause foaming or the like in the liquid L. The air inside 2 can be replaced with the liquid L.

Further, in the liquid blow molding method of the present embodiment, since the gas-liquid separation step is also performed while performing the gas-liquid replacement step, air is efficiently separated from the liquid L supplied to the preform 2. The amount of air remaining inside the preform 2 can be further reduced.

Further, when the gas-liquid separation step is performed after the gas-liquid replacement step is completed, the air on the bottom side of the preform 2 is surely separated from the liquid L so that the inside of the preform 2 is separated. The amount of air remaining in the air can be further reduced.

Further, in the liquid blow molding method of the present embodiment, in the gas-liquid separation step, the preform 2 or the mold 10 is subjected to ultrasonic waves to vibrate the preform 2, so that the preform 2 is finely divided at high speed. It can be vibrated, which allows the air to be more efficiently separated from the liquid L supplied to the preform 2.

Further, in the gas-liquid separation step, when the preform 2 or the mold 10 is brought into contact with the vibrating body to vibrate the preform 2, it is possible to give a strong vibration to the preform 2 and the liquid L. Even when the viscosity of the preform 2 is high, air can be efficiently separated from the liquid L supplied to the preform 2.

Further, the liquid blow molding method of the present embodiment includes a nozzle engagement step of engaging the blow nozzle 23 with the mouth portion 2a before the gas-liquid replacement step, and in the gas-liquid replacement step, the blow nozzle 23 While supplying the liquid L from the mouth portion 2a to the inside of the preform 2 through the liquid supply port 23a, the air inside the preform 2 is sent to the outside from the discharge port 23b provided in the blow nozzle 23 separately from the liquid supply port 23a. Since the liquid L is discharged to the outside, the air inside the preform 2 can be discharged to the outside without leaking the liquid L to the outside.

It goes without saying that the present invention is not limited to the above-described embodiment and can be variously modified without departing from the gist thereof.

For example, in the above-described embodiment, the case where the liquid blow molding method of the present invention is performed using the liquid blow molding apparatus 1 having the configuration shown in FIG. The liquid blow molding method of the present invention can also be performed.

Further, in the above-described embodiment, the blow nozzle 23 is provided with a discharge port 23b for discharging the air inside the preform 2 to the outside in the gas-liquid replacement step. It may be provided at the site.

Further, in the above-described embodiment, in the gas-liquid separation step, the ultrasonic waves generated from the vibration generator 40 built in the mold 10 are applied to the preform 2 in a non-contact manner to cause the preform 2 to vibrate at high speed. However, the present invention is not limited to this, and if the preform 2 can be vibrated, for example, the vibration generator 40 is brought into contact with the preform 2 (for example, the mouth 2a) to cause the preform 2 to vibrate slightly at high speed. It may be configured such that the ultrasonic waves generated by the vibration generator 40 arranged outside the mold 10 are applied to the mold 10 in contact or non-contact to cause the preform 2 to vibrate at high speed together with the mold 10. Well, the ultrasonic waves generated by the vibration generator 40 arranged between the mold 10 and the nozzle unit 20 are applied to the mouth portion 2a of the preform 2 in contact or non-contact to cause the preform 2 to vibrate slightly at high speed. Further, the structure may be such that the ultrasonic waves generated by the vibration generator 40 provided in the nozzle unit 20 are applied to the mouth portion 2a of the preform 2 in contact or non-contact to cause the preform 2 to vibrate slightly at high speed. In addition, the preform 2 may be vibrated at high speed together with the nozzle unit 20 by applying the ultrasonic waves generated by the vibration generator 40 provided on the outside of the nozzle unit 20 to the nozzle unit 20 in contact or non-contact. .. Further, the sound wave applied to the preform 2 is not limited to the ultrasonic wave, and may be a sound wave having a frequency of less than 20 kHz.

Further, in the above-described embodiment, the vibration generated by the vibration generator 40 is used as an ultrasonic wave to cause the preform 2 to be slightly vibrated at high speed by the ultrasonic wave. However, by vibrating the preform 2, the preform 2 is vibrated. If it is possible to separate air from the liquid L inside, the vibration generated by the vibration generator 40, that is, the method of generating the vibration applied to the preform 2 by the vibration generator 40, and the number and amplitude of the vibrations can be changed as appropriate. Is.

Further, in the above-described embodiment, in the gas-liquid replacement step, the air inside the preform 2 is discharged to the outside from the discharge port 23b provided in the blow nozzle 23, but the present invention is not limited to this. Before the step, the blow nozzle 23 is lowered to the first position where the mouth portion 2a is not sealed (first nozzle lowering step), and in the gas-liquid replacement step, the blow nozzle 23 at the first position is passed through the blow nozzle 23 from the mouth portion 2a. While supplying the liquid L to the inside of the reform 2, the air inside the preform 2 may be discharged to the outside through the gap between the blow nozzle 23 and the mouth portion 2a. In this case, after the gas-liquid replacement step, the blow nozzle 23 is lowered to the second position where the mouth portion 2a is sealed (second nozzle lowering step), and then the blow molding step is performed. With such a configuration, it is possible to simplify the configuration of the liquid blow molding apparatus 1 by eliminating the need to provide the discharge port 23b in the blow nozzle 23, and to reduce the manufacturing cost of the liquid-containing container C molded by the liquid blow molding method. it can.

Further, in the above-described embodiment, biaxial stretching blow molding is performed using the stretching rod 28 in the blow molding step, and the stretching rod 28 is pulled out from the liquid-containing container C to increase the headspace HS. The head space HS may not be formed by the stretching rod 28 (for example, the stretching rod 28 may be pulled out before the end of the blow molding step).

Further, in the above-described embodiment, the pump 30 is a plunger pump, but the pump 30 is not limited to this, and the liquid L can be pressurized to a predetermined pressure and supplied to the preform 2, and after molding. Pumps having various configurations can be used as long as a predetermined amount of liquid L can be sucked back from the inside of the liquid container C.

Further, the liquid blow molding method of the present invention requires a large headspace HS inside the container C containing a liquid used for a container with a pump for containing a relatively viscous content liquid such as shampoo or liquid detergent. It is preferably applied when molding a product, but it can also be applied to molding various liquid-containing containers C regardless of the size of the headspace HS.

Further, the gas-liquid separation step may be performed during the blow molding step or after the blow molding step, but since the blow molding step is basically performed in a sealed state of the preform 2, the liquid L It is difficult to remove the air separated from the outside. Therefore, it is preferable that the gas-liquid separation step is performed together with the gas-liquid replacement step or after the gas-liquid replacement step and before the blow molding step.

1 Liquid blow molding device 2 Preform 2a Mouth 2b Body 10 Mold 11 Cavity 20 Nozzle unit 21 Main body block 22 Support block 22a Connection port 23 Blow nozzle 23a Liquid supply port 23b Discharge port 23c Connection path 24 Supply path 25 Supply port 26 Sealed body 27 Shaft body 28 Stretching rod 30 Pump 30a Cylinder 30b Piston 31 Supply tank 40 Vibration generator P1 Piping V1 On-off valve P2 Piping V2 On-off valve C Liquid container

Claims (8)

A liquid blow molding method in which a synthetic resin preform having a mouth is molded into a container containing a liquid having a predetermined shape.
A gas-liquid replacement step of supplying a liquid from the mouth to the inside of the preform through a blow nozzle and discharging the air inside the preform to the outside.
A gas-liquid separation step of vibrating the preform to separate air from the liquid inside the preform.
After the gas-liquid separation step, the blow molding step of supplying a pressurized liquid from the mouth portion to the inside of the preform through the blow nozzle to mold the preform into a container having a predetermined shape is provided. A characteristic liquid blow molding method. The liquid blow molding method according to claim 1, wherein the gas-liquid separation step is also performed while performing the gas-liquid replacement step. The liquid blow molding method according to claim 1, wherein the gas-liquid separation step is performed after the completion of the gas-liquid replacement step. The liquid blow molding method according to any one of claims 1 to 3, wherein in the gas-liquid separation step, the preform or a mold to which the preform is mounted is subjected to ultrasonic waves to vibrate the preform. .. The liquid blow molding according to any one of claims 1 to 3, wherein in the gas-liquid separation step, the preform or a mold to which the preform is mounted is brought into contact with a vibrating body to vibrate the preform. Method. Prior to the gas-liquid replacement step, a nozzle engaging step of engaging the blow nozzle with the mouth portion is provided.
In the gas-liquid replacement step, while supplying liquid from the mouth portion to the inside of the preform through the liquid supply port of the blow nozzle, the pump is provided from a discharge port provided in the blow nozzle separately from the liquid supply port. The liquid blow molding method according to any one of claims 1 to 5, wherein the air inside the remodeling is discharged to the outside. Prior to the gas-liquid replacement step, there is a first nozzle lowering step of lowering the blow nozzle to a first position where the mouth portion is not sealed.
In the gas-liquid replacement step, while supplying liquid from the mouth to the inside of the preform through the blow nozzle at the first position, the inside of the preform is supplied from the gap between the blow nozzle and the mouth. Exhaust air to the outside
After the gas-liquid replacement step, there is a second nozzle lowering step of lowering the blow nozzle to a second position for sealing the mouth portion.
The liquid blow molding method according to any one of claims 1 to 5, wherein the blow molding step is performed after the second nozzle lowering step. The liquid blow molding method according to any one of claims 1 to 7, further comprising a suckback step of sucking back a predetermined amount of liquid from the inside of the container after molding through the blow nozzle after the blow molding step.

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